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| United States Patent |
5,292,808
|
|
Ohmae
, et al.
|
March 8, 1994
|
Multi-phase structure and process for producing the same
Abstract
A polyamide resin composition having a multi-phase structure and a process
for producing the same are disclosed, the composition comprising:
(A) from 60 to 97 parts by weight of a polyamide resin containing at least
2 parts by weight of (A-1) a polyamide resin having a concentration ratio
of terminal carboxyl group to terminal amino group of 1.5 or more,
(B) from 3 to 40 parts by weight of an ethylene copolymer comprising:
(a) from 40 to 90% by weight of an ethylene unit,
(b) from 5 to 60% by weight of an .alpha.,.beta.-unsaturated carboxylic
acid alkyl ester unit, and
(c) from 0.3 to 10% by weight of a maleic anhydride unit, and
(C) from 0.01 to 20 parts by weight, per 100 parts by weight of the sum of
the components (A) and (B), of a polyfunctional compound having at least
two functional groups reactive to a carboxylic anhydride group or a
carboxyl group in the molecule thereof,
a part of the polyamide resin (A) constituting a matrix phase, the ethylene
copolymer (B) constituting a first-order disperse phase, and the rest of
the polyamide resin (A) constituting a second-order disperse phase in the
first-order disperse phase.
The composition has well-balanced physical properties, such as impact
resistance, rigidity, and thermal resistance, and excellent moldability.
A process for producing the above multi-phase structure is also included,
in which a part of a polyamide resin constitutes a matrix phase, an
ethylene copolymer constitutes a first order dispersed phase, and the rest
of the polyamide resin constitutes a second order dispersed phase in the
first order dispersed phase.
| Inventors:
|
Ohmae; Tadayuki (Chiba, JP);
Toyoshima; Yoshiki (Chiba, JP);
Mashita; Kentaro (Chiba, JP);
Yamaguchi; Noboru (Chiba, JP);
Nambu; Jinsho (Tokyo, JP)
|
| Assignee:
|
Sumitomo Chemical Company, Limited (Osaka, JP)
|
| Appl. No.:
|
072695 |
| Filed:
|
June 7, 1993 |
Foreign Application Priority Data
| Current U.S. Class: |
525/113; 525/66; 525/179; 525/181; 525/182; 525/183 |
| Intern'l Class: |
C08L 077/00 |
| Field of Search: |
525/183,179,181,182,66,113
|
References Cited
U.S. Patent Documents
| 5047478 | Sep., 1991 | Ohmae et al. | 525/183.
|
| Foreign Patent Documents |
| 0258040 | Mar., 1988 | EP.
| |
| 0284379 | Sep., 1988 | EP.
| |
Other References
Patent Abstracts of Japan, vol. 7, No. 209.
Patent Abstracts of Japan, vol. 13, No. 221.
|
Primary Examiner: Carrillo; Ana L.
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak & Seas
Parent Case Text
This is a continuation of application Ser. No. 07/477,383 filed Feb. 9,
1990 now abandoned.
Claims
What is claimed is:
1. A multi-phase structure comprising:
(A) from 70 to 97 parts by weight of a polyamide resin containing
(A-1) at least 2 parts by weight, per 100 parts by weight of the sum of the
components (A) and (B), of a polyamide resin having a concentration ratio
of terminal carboxyl group to terminal amino group of 1.5 or more,
(B) from 3 to 30 parts by weight of an ethylene copolymer comprising:
(a) from 40 to 90% by weight of an ethylene unit,
(b) from 5 to 60% by weight of an .alpha.,.beta.-unsaturated carboxylic
acid alkyl ester unit, and
(c) from 0.3 to 10% by weight of a maleic anhydride unit,
with the sum of the components (a), (b) and (c) being 100% by weight, and
(C) from 0.01 to 20 parts b weight, per 100 parts by weight of the sum of
the components (A) and (B), of a compound selected from the group
consisting of an aliphatic diamine carbamate, an aliphatic polyamine, an
alicyclic polyamine, an aromatic amine, an ethylene copolymer comprising
an ethylene unit and an N,N-dialkylaminoalkyl, .alpha.,.beta.-unsaturated
carboxylic acid ester unit, an ethylene copolymer comprising an ethylene
unit and an N,N-dialkylaminoalkyl .alpha.,.beta.-unsaturated carboxylic
acid amide unit, and a compound having at least two epoxy groups in the
molecule thereof, and
wherein a part of the polyamide resin (A) constitutes a matrix phase, the
ethylene copolymer (B) constitutes a first-order disperse phase, and the
remainder of the polyamide resin (A) constitutes a second-order disperse
phase in the first-order disperse phase.
2. A multi-phase structure as claimed in claim 1, wherein the ethylene
copolymer (B) comprises (a) from 65 to 90% by weight of an ethylene unit,
(b) from 10 to 35% by weight of an .alpha.,.beta.-unsaturated carboxylic
acid alkyl ester unit, and (c) from 1 to 5% by weight of a maleic
anhydride unit, with the sum of the components (a), (b) and (c) being 100%
by weight.
3. A multi-phase structure as claimed in claim 1, wherein the compound (C)
is an aliphatic diamine carbamate.
4. A multi-phase structure as claimed in claim 1, wherein the
polyfunctional compound (C) is an ethylene copolymer comprising an
ethylene unit and an N,N-dialkylaminoalkyl .alpha.,.beta.-unsaturated
carboxylic acid ester unit, or an ethylene copolymer comprising an
ethylene unit and an N,N-dialkylaminoalkyl .alpha.,.beta.-unsaturated
carboxylic acid amide unit.
5. A multi-phase structure as claimed in claim 1, wherein the
polyfunctional compound (C) is an ethylene copolymer comprising an
ethylene unit and a glycidyl .alpha.,.beta.-unsaturated carboxylate unit;
an ethylene copolymer comprising an ethylene unit, a glycidyl
.alpha.,.beta.-unsaturated carboxylate unit, and an alkyl
.alpha.,.beta.-unsaturated carboxylate unit; or an ethylene copolymer
comprising an ethylene unit, a glycidyl .alpha.,.beta.-unsaturated
carboxylate unit, and a vinyl carboxylate unit.
6. A multi-phase structure as claimed in claim 1, wherein the compound for
component (C) is an aliphatic polyamine, and the aliphatic polyamine is an
aliphatic diamine.
7. A multi-phase structure prepared by a process comprising:
a step of melt-kneading (A-1) from 20 to 60 parts by weight of a polyamide
resin having a concentration ratio of terminal carboxyl group to terminal
amino group of 1.5 or more with (B) from 40 to 80 parts by weight of an
ethylene copolymer comprising:
(a) from 40 to 90% by weight of an ethylene unit,
(b) from 5 to 60% by weight of an .alpha.,.beta.-unsaturated carboxylic
acid alkyl ester unit, and
(c) from 0.3 to 10% by weight of a maleic anhydride unit, with the sum of
components (a), (b) and (c) being 100% by weight,
to prepare a composition (I),
a step of melt-kneading 100 parts by weight of the composition (I) with (C)
from 0.01 to 20 parts by weight of a compound selected from the group
consisting of an aliphatic diamine carbamate, an aliphatic polyamine, an
alicyclic polyamine, an aromatic amine, an ethylene copolymer comprising
an ethylene unit and an N,N-dialkylaminoalkyl .alpha.,.beta.-unsaturated
carboxylic acid amide unit, and a compound having at least two epoxy
groups in the molecule thereof to prepare a composition (II), and
a step of melt-kneading 100 parts by weight of the composition (II) with
from 50 to 1,000 parts by weight of a polyamide resin.
Description
FIELD OF THE INVENTION
This invention relates to a multi-phase structure of a polyamide resin
composition which is excellent in impact resistance and processing
fluidity and is easily molded by injection molding or extrusion molding to
provide various molded articles, sheets and films and to a process for
producing the same. More particularly, it relates to a multi-phase
structure of a polyamide resin composition having excellent impact
resistance as well as excellent processing fluidity which is obtained by
melt-kneading a specific polyamide resin with an ethylene copolymer
containing a maleic anhydride unit in a specific compounding mode and to a
process for producing the same.
BACKGROUND OF THE INVENTION
Polyamide resins are generally excellent in rigidity, abrasion resistance,
chemical resistance, thermal resistance, and electrical characteristics
and have therefore been widely employed as engineering plastics.
Polyamide resins, however, still leave room for improvements in impact
resistance, molding stability and the like, which have constituted
hindrances in exploiting their utility. Thus, various proposals have
hitherto been made to improve impact resistance of polyamide resins.
Typical proposals include a reinforced multi-phase thermoplastic resin
composition comprising a polyamide having dispersed therein an ethylene
copolymer, e.g., an ethylenemaleic anhydride-acrylic ester copolymer, to a
particle size of from 0.01 to 1.0 .mu.m as disclosed in JP-B-55-44108 (the
term "JP-B" as used herein means an "examined Japanese patent
publication"); a high-impact polyamide comprising a polyamide having
dispersed therein a maleic anhydride-modified ethylene-propylene rubber to
a particle size of not more than 0.36 .mu.m as disclosed in JP-A-60-221453
(the term "JP-A" a used herein means an "unexamined published Japanese
patent application"); and a high-impact polyamide resin composition
comprising a polyamide having dispersed therein an ionomer resin to a
particle size of from 0.005 to 3 .mu.m as disclosed in JP-A-58-108251.
It is well known, as stated above, that properties of a polyamide resin
composition greatly depend on the dispersed state, i.e., the micro-phase
separation structure, of the constituent polymer. It is hence important to
elaborate on the optimum phase separation structure for manifestation of
excellent physical properties. Most of the so far proposed impact
resistant polyamide resins have revealed through microscopic observation a
simple two-phase separation structure (particle structure) called
sea-island structure in which a second component having rubbery properties
is finely dispersed as a particulate phase (island phase) in a polyamide
matrix phase (sea phase).
The latest report, POLYMER COMMUNICATIONS, Vol. 29, pp. 163 (1988),
describes that polyamide 6.6 and 20% by weight a maleic anhydride-modified
ethylene-propylene rubber are melt-kneaded in a 30 mm.phi. twin-screw
extruder to provide a multi-phase structure. According to the examination
by the present inventors, however, since the multi-phase structure in this
report is unstable, if the compound is further melt-kneaded or a part or
the whole of the sprue and runner is recycled to injection molding, etc,
it has turned out that the multi-phase structure becomes a sea-island
two-phase structure and, also, various physical properties are
deteriorated.
It is also known that polyamide resins having a higher terminal amino group
concentration give better results as disclosed in JP-B-62-25182,
suggesting use of a polyamide resin having a concentration ratio of
terminal amino group to terminal carboxyl group of 3.5 or more and in
JP-A-59-164359, teaching use of a polyamide resin having a terminal amino
group concentration of 5.5.times.10.sup.-5 eq./g or more. Further,
JP-B-61-37305 proposes use of a polyamide resin having a relative
viscosity of at least 3.5.
It has also been disclosed in JP-A-63-199755 and JP-A-63-235365 that a
combined use of an ethylene-(meth)acrylic ester-maleic anhydride copolymer
with a polyfunctional compound as a partial crosslinking agent provides a
polyamide resin composition exhibiting fairly improved impact resistance
over the conventional polyamide resins, but the composition is still
insufficient in maintaining physical properties, such as thermal
resistance, rigidity, impact resistance, and processability, in a good
balance. That is, the improved impact resistance and softness are offset
by other mechanical properties poorer than those of a polyamide resin per
se, such as rigidity, tensile strength, hardness, thermal resistance, and
processability.
It has turned out that the conventional sea-island structure has its own
limit in making a balance between impact resistance and rigidity of a
polyamide resin which are conflicting with each other while satisfying
molding processability, i.e., high fluidity. In other words, a specific
phase separation structure should be established before a material
exhibiting impact resistance combined with rigidity, thermal resistance,
and moldability can be obtained. None of the above-described conventional
techniques is based on this point of view.
SUMMARY OF THE INVENTION
An object of this invention is to provide a two-component system polyamide
resin composition comprising a polyamide resin and a specific ethylene
copolymer in a multi-phase structure having a specific multi-phase
separation structure, which has excellent characteristics, such as impact
resistance, rigidity and thermal resistance, and excellent moldability.
Another object of this invention is to provide a process for producing the
above-described polyamide resin composition.
The inventors have extensively and intensively investigated modification of
a polyamide resin on the basis of the above-described viewpoint. As a
result, they have found that a multi-phase structure having well-balanced
impact resistance, thermal resistance, rigidity and molding processability
can be obtained by melt-kneading a specific polyamide resin, a specific
ethylene copolymer, and a specific polyfunctional compound in a specific
manner, thus having reached the present invention.
This invention provides a multi-phase structure comprising:
(A) from 60 to 97 parts by weight of a polyamide resin containing at least
2. parts by weight of (A-1) a polyamide resin having a concentration ratio
of terminal carboxyl group to terminal amino group of 1.5 or more,
(B) from 3 to 40 parts by weight of an ethylene copolymer comprising:
(a) from 40 to 90% by weight of an ethylene unit,
(b) from 5 to 60% by weight of an .alpha.,.beta.-unsaturated carboxylic
acid alkyl ester unit, and
(c) from 0.3 to 10% by weight of a maleic anhydride unit, and
(C) from 0.01 to 20 parts by weight, per 100 parts by weight of the sum of
the components (A) and (B), of a polyfunctional compound having at least
two functional groups reactive to a carboxylic anhydride group or a
carboxyl group in the molecule thereof,
a part of the polyamide resin (A) constituting a matrix phase, the ethylene
copolymer (B) constituting a first-order disperse phase, and the rest of
the polyamide resin (A) constituting a second-order disperse phase in the
first-order disperse phase.
This invention further provides a process for producing a multi-phase
structure in which a part of a polyamide resin constitutes a matrix phase,
an ethylene copolymer constitutes a first-order disperse phase, and the
rest of the polyamide resin constitutes a second-order disperse phase in
the first-order disperse phase, which comprises:
a step of melt-kneading (A-1) from 20 to 60 parts by weight of a polyamide
resin having a concentration ratio of terminal carboxyl group to terminal
amino group of 1.5 or more with (B) from 40 to 80 parts by weight of an
ethylene copolymer comprising:
(a) from 40 to 90% by weight of an ethylene unit,
(b) from 5 to 60% by weight of an .alpha.,.beta.-unsaturated carboxylic
acid alkyl ester unit, and
(c) from 0.3 to 10% by weight of a maleic anhydride unit,
to prepare a composition (I),
a step of melt-kneading 100 parts by weight of the composition (I) with (C)
from 0.01 to 20 parts by weight of a polyfunctional group containing at
least two functional groups reactive to a carboxylic anhydride group or a
carboxyl group in the molecule thereof to prepare a composition (II), and
a step of melt-kneading 100 parts by weight of the composition (II) with
from 50 to 1,000 parts by weight of a polyamide resin.
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 1 and 5 each shows a transmission electron micrograph of the
multi-phase structure according to the present invention.
FIGS. 2, 3, 4, and 6 each shows a transmission electron micrograph of a
particle structure according to the conventional techniques.
DETAILED DESCRIPTION OF THE INVENTION
Polyamide resins which can be used in the present invention include various
kinds obtainable by polycondensation of a lactam having a ring with at
least three members, a polymerizable .omega.-amino acid, or a dibasic acid
and a diamine.
Specifically, there can be mentioned polymers of .epsilon.-caprolactam,
aminocaproic acid, enantholactam, 7-aminoheptanoic acid, or
11-aminoundecanoic acid; polymers obtained by polycondensation of a
diamine (e.g., butanediamine, hexamethylenediamine, nonamethylenediamine,
undecamethylenediamine, dodecamethylenediamine, and metaxylenediamine) and
a dicarboxylic acid (e.g., terephthalic acid, isophthalic acid, adipic
acid, sebacic acid, dodecanedibasic acid, and glutaric acid); and
copolymers of these units.
Specific examples of the polyamide resin are aliphatic polyamide resins,
e.g., polyamide 4.6, polyamide 6, polyamide 6.6, polyamide 6.10, polyamide
11, polyamide 12, and polyamide 6.12; and aromatic polyamide resins, e.g.,
poly(hexamethylenediamine terephthalamide) and poly(hexamethylene
isophthalamide). Preferred of them are polyamide 6, polyamide 6.6, and
polyamide 12.
In addition, various copolymer nylon resins having a melting point of from
80.degree. to 200.degree. C. which are commercially available for use as
hot-melt adhesives are also employable either individually or in
combination with polyamide resins having a melting point of 200.degree. C.
or higher.
In the multi-phase structure of the present invention, the polyamide resin
(A) is a polyamide resin containing at least 2 parts by weight of a
polyamide resin (A-1) having a concentration ratio of terminal carboxyl
group to terminal amino group of 1.5 or more in 60 to 97 parts by weight
of a polyamide resin. If the content of the polyamide resin (A-1) is less
than 2 parts by weight, a multi-phase structure having well-balanced
physical properties cannot be obtained, and the composition is poor in
molding processability.
In the process according to the present invention, the polyamide resin
(A-1) constituting the composition (I) is a polyamide resin having a
concentration ratio of terminal carboxyl group to terminal amino group of
1.5 or more. If this concentration ratio is less than 1.5, a multi-phase
structure having well-balanced physical properties cannot be produced, and
the finally obtained composition is poor in molding processability. The
polyamide resin to be compounded into the composition (II) is not
particularly limited, and any kind of polyamide resins may be used.
The ethylene copolymer (B) which can be used in this invention
comprises-from 40 to 90% by weight, preferably from 65 to 90% by weight,
of an ethylene unit (a), from 5 to 60% by weight, preferably from 10 to
35% by weight, of an .alpha.,.beta.-unsaturated carboxylic acid alkyl
ester unit (b), and from 0.3 to 10% by weight, preferably from 1 to 5% by
weight, of a maleic anhydride unit (c).
The .alpha.,.beta.-unsaturated carboxylic acid alkyl ester unit (b) is an
alkyl ester of an unsaturated carboxylic acid containing from 3 to 8
carbon atoms, e.g., acrylic acid and methacrylic acid. Specific examples
of the .alpha.,.beta.-unsaturated carboxylic acid alkyl ester unit (b) are
methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate,
n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, methyl
methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl
methacrylate, n-butyl methacrylate, and isobutyl methacrylate, with methyl
acrylate, ethyl acrylate, n-butyl acrylate, and methyl methacrylate being
particularly preferred.
As far as the desired performance properties are assured, ethylene
copolymers containing other copolymerizable monomer units, e.g., vinyl
acetate and vinyl propionate, may also be used in this invention.
If the content of the ethylene unit (a) in the ethylene copolymer (B) is
less than 40% by weight, the resulting polyamide composition has
considerably reduced rigidity. If it exceeds 90% by weight, the resulting
polyamide composition has reduced impact resistance. If the content of the
.alpha.,.beta.-unsaturated carboxylic acid alkyl-ester unit (b) in the
ethylene copolymer (B) is less than 5% by weight, the effect of improving
impact resistance is small. If it exceeds 60% by weight, the resulting
composition has considerably reduced rigidity. If the content of the
maleic anhydride unit (c) in the ethylene copolymer (B) is less than 0.3%
by weight, the composition has insufficient impact resistance, and if it
exceeds 10% by weight, molding processability is reduced.
The ethylene copolymer (B) preferably has a melt index of from 1 to 100
g/10 min, more preferably from 2 to 50 g/10 min, as measured according to
JIS K6760. If the melt index of the ethylene copolymer (B) exceeds 100
g/10 min, the polyamide composition has insufficient mechanical
properties. If it is less than 1 g/10 min, the ethylene copolymer (B)
lacks compatibility with a polyamide resin.
The polyfunctional compound (C) which can be used in the present invention
is a polyfunctional compound containing at least two functional groups
which are reactive to a carboxylic anhydride group or a carboxyl group in
the molecule thereof, preferably a polyfunctional compound containing at
least two functional groups selected from the group consisting of an amino
group, an epoxy group, and a hydroxyl group in the molecule thereof. The
polyfunctional compound (C) is not limited in molecular weight and
includes high-molecular weight compounds as well. The polyfunctional
compound (C) chiefly functions as a partial crosslinking agent for the
ethylene copolymer (B) containing the maleic anhydride unit (c), serving
to improve various physical properties of the multi-phase structure.
Specific preferable examples of the polyfunctional compound containing two
or more amino groups in the molecule thereof include aliphatic diamines,
e.g.,
1,6-hexamethylenediamine,trimethylhexamethylenediamine,1,4-diaminobutane,1
,3-diaminopropane, ethylenediamine, and polyetherdiamine; aliphatic diamine
carbamates, e.g., hexamethylenediamine carbamate and ethylenediamine
carbamate; aliphatic polyamines, e.g., diethylenetriamine,
triethylenetetramine,
tetraethylenepentamine,pentaethylenehexamine,ethylaminoethylamine,methyl-a
minopropylamine, 2-hydroxyethylaminopropylamine, aminoethylethanolamine,
1,3-bis(3-aminopropoxy)-2,2-dimethylpropane, 1,3,6-trisaminomethylhexane,
iminobispropylamine, methyliminobispropylamine, and
bis(hexamethylene)triamine; alicyclic polyamines, e.g., menthenediamine,
N-aminoethylpiperazine, 1,3-diaminocyclohexane, isophoronediamine, and
bis(4-amino-3-methylcyclohexyl)methane; aliphatic polyamines having an
aromatic ring, e.g., m-xylylenediamine; aromatic amines, e.g.,
diaminodiphenyl ether, 4,4'-methylenedianiline, diaminodiphenylsulfone,
benzidine, 4,4'-bis(o-toluidine), 4,4'-thiodianiline, dianisidine,,
methylenebis(o-chloroaniline), bis(3,4-diaminophenyl) sulfone, and
diaminoditolyl sulfone; polyamines containing silicon, .e.g.,
1,3-bis(y-aminopropyl)-1,1,3,3-tetramethyldisiloxane; amine-modified
silicone oils; amine-terminated butadiene-acrylonitrile copolymers;
tertiary amine compounds, e.g., N,N,N',N'-tetramethylhexamethylenediamine
and N,N,N',N",N"-pentamethyldiethylenetriamine; ethylene copolymers
comprising an ethylene unit and an N,N-dialkylaminoalkyl
.alpha.,.beta.-unsaturated carboxylic acid ester unit, e.g., an
ethylene-N,N-dimethylaminoethyl methacrylate copolymer; and ethylene
copolymers comprising an ethylene unit and an N,N-dialkylaminoalkyl
.alpha.,.beta.-unsaturated carboxylic acid amide unit, e.g., an
ethylene-N,N-dimethylaminopropylacrylamide copolymer.
The polyfunctional compound containing two or more epoxy groups in the
molecule thereof is roughly divided into epoxy group-containing olefin
copolymers and epoxy compounds.
Specific preferable examples of the epoxy group-containing olefin copolymer
are copolymers of an olefin and glycidyl methacrylate and/or glycidyl
acrylate. The olefin includes ethylene, propylene, butene-1, and
isobutylene, with ethylene being preferred. The epoxy group-containing
olefin copolymer may further contain, as a copolymerization component, an
.alpha.,.beta.-unsaturated carboxylic acid alkyl ester or a carboxylic
acid vinyl ester, such as alkyl esters of acrylic acid, methacrylic acid,
etc., e.g., methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl
methacrylate, vinyl acetate, and vinyl propionate. Also included are
glycidyl methacrylate-modified ethylene-propylene rubbers and
ethylene-methyl acrylateglycidyl methacrylate copolymers.
The epoxy group-containing olefin copolymer may be prepared by any of
random copolymerization, block copolymerization, and graft
copolymerization. The content of the glycidyl methacrylate unit and/or
glycidyl acrylate unit in the copolymer is selected from the range of 1 to
50% by weight. Outside this range, the effects of improving physical
properties are insufficient.
The epoxy compound includes glycidyl ethers of bisphenols, e.g., bisphenol
A, resorcinol, and hydroquinone, and glycidyl ethers of halogenated
bisphenols. Preferred of them are epoxy resins. These epoxy compounds are
used either individually or as a mixture of two or more thereof.
In general, the epoxy compound is employed in combination with a curing
agent, such as amines, acid anhydrides, polymercaptanes, and phenolic
resins. While in the present invention no curing agent is usually used, it
may be added, if desired, in such an amount that the amount of active
hydrogen of the curing agent is not more than an amount equimolar with the
epoxy group-containing component.
Suitable examples of the epoxy resin include bisphenol A type epoxy resins,
bisphenol F type epoxy resins, novolak type, epoxy resins, cyclic
aliphatic epoxy resins, glycidyl ester type resins, glycidylamine type
resins, hydantoin type epoxy resins, and triglycidyl isocyanurate.
The polyfunctional compound containing two or more hydroxyl groups in the
molecule thereof includes trimethylolpropane, pentaerythritol, and a
saponification product of an ethylene-vinyl acetate copolymer.
Compounds containing two or more dihydroxazolyl groups in the molecule
thereof, e.g., 2,2,-(1,3-phenylene)-bis(2-oxazoline) and a
styrene-vinyloxazoline copolymer, can also be used as the polyfunctional
compound (C).
In the multi-phase structure of the invention, the polyamide resin (A) is
present in an amount of from 60 to 97 parts by weight, preferably from 70
to 90 parts by weight; and the ethylene copolymer (B) is present in an
amount of from 3 to 40 parts by weight, preferably from 10 to 30 parts by
weight. If the content of the polyamide resin (A) is less than 60 parts by
weight, rigidity and thermal resistance are insufficient. If it exceeds 97
parts by weight, impact resistance is insufficient.
The amount of the polyfunctional compound (C) in the multi-phase-structure
should be adjusted depending on its reactivity to a carboxylic anhydride
group or a carboxyl group. It is usually from 0.01 to 20 parts by weight
per 100 parts by weight of the sum of components (A) and (B). If the
amount is less than 0.01 part by weight, mechanical properties such as
thermal resistance and rigidity cannot be effectively improved. Even if it
exceeds.20 parts by weight, no further effects can be expected.
In carrying out the process for producing the multi-phase structure
according to the present invention, the composition (I) obtained by the
first melt-kneading step comprises from 20 to 60 parts by weight of the
polyamide resin (A-1) and from 40 to 80 parts by weight of the ethylene
copolymer (B). If the content of the polyamide resin (A-1) is less than 20
parts by weight, the finally obtained multi-phase structure does not have
sufficient rigidity and thermal resistance. If it exceeds 60 parts by
weight, impact resistance of the multi-phase structure is unsatisfactory.
While the amount of the polyfunctional compound (C) to be added in the
second melt-kneading step should be adjusted taking into consideration
reactivity of the polyfunctional compound (C) to a carboxylic anhydride
group or a carboxyl group, it usually ranges from 0.01 to 20 parts by
weight per 100 parts by weight of the composition (I). If it is less than
0.01 part by weight, mechanical properties of the multi-phase structure,
such as thermal resistance and rigidity, are not effectively improved.
Even if it exceeds 20 parts by weight, no further effects are obtained.
The amount of the polyamide resin to be added in the third melt-kneading
step ranges from 50 to 1000 parts by weight per 100 parts by weight of the
composition (II). If it is less than 50 parts by weight, rigidity and
thermal resistance are insufficient. If it exceeds 1,000 parts by weight,
impact resistance is unsatisfactory.
In the present invention, a proportion of a polyamide resin having an amino
group at both terminals thereof is minimized as far as possible by using
the polyamide resin (A-1) having a concentration ratio of terminal
carboxyl group to terminal amino group of 1.5 or more as a part or the
whole of the polyamide resin. When a polyamide resin having an amino group
at both terminals thereof (hereinafter referred to as PA) is melt-kneaded
with the ethylene copolymer (B), there is formed a crosslinked block
structure --PA--B--PA--B--PA--, which reduces the function as an adhesive
(compatibilizer) between the polyamide .resin and the ethylene copolymer,
resulting in an increased melt viscosity and a decreased processability.
When in sing a polyamide resin having an amino group at one terminal
thereof (hereinafter referred to as PA'), a grafted block structure
PA'--B--PA' is formed, effectively functioning as an adhesive
(compatibilizer) between a polyamide resin and an ethylene copolymer while
suppressing an increase in melt viscosity and retaining satisfactory
processability.
JP-A-63-199755 and JP-A-63-235365 disclose a combined use of an
ethylene-(meth)acrylic ester-maleic anhydride copolymer with a
polyfunctional compound as a partial cross-linking agent. However, the
polyamide resins used in the working examples of these .publications are
those having a concentration ratio of terminal carboxyl group to terminal
amino group of less than 1.5 as tabulated below.
______________________________________
Polyamide 6
Polyamide 6.6
"A1020BRL"
"A125"
______________________________________
Concentration of
60 56
terminal amino
group (eq./10.sup.6 g)
Concentration of
60 70
terminal carboxyl
group (eq./10.sup.6 g)
Concentration ratio
1.0 1.25
of terminal carboxyl
group to terminal
amino group
______________________________________
As a result, formation of a multi-phase structure is insufficient, and also
the multi-phase structure is easily destroyed on melt-kneading in a
twin-screw extruder, thus failing to produce sufficient improving effects.
Besides, the resulting blend has poor processability due to high melt
viscosity.
Hence, the present invention is characterized by using a polyamide resin
having a specific terminal group structure as defined above thereby
improving the conventional techniques.
The process for producing the multi-phase structure according to the
present invention is a process of kneading constituent components in a
molten state. Kneading in a molten state (melt-kneading) can be carried
out by using generally employed various extruders of single-screw type or
twin-screw type, a Banbury mixer, rolls, and various kneaders.
The multi-phase structure of the present invention is like a structure of
salami, in which a part of the polyamide resin constitutes a matrix phase,
the partially crosslinked ethylene copolymer constitutes a first-order
disperse phase which is chemically bonded to the matrix phase, and the
rest of the polyamide resin is further dispersed in the first-order
disperse phase to constitute a second-order disperse phase which is
chemically bonded to the first-order disperse phase.
If the maximum particle size of the first-order disperse phase is too
small, not only does crystallinity of the matrix phase tend to be
impaired, but molding processability, i.e., flow characteristics, tends to
be deteriorated. On the other hand, too a large maximum particle size
tends to reduce impact resistance, giving a deteriorated appearance of
molded articles. Accordingly, a preferred particle size of the first-order
disperse phase ranges from about 0.1 to 10 .mu.m, particularly from 0.2 to
5 .mu.m. Better results are obtained as the ratio of (number of particles
greater than 1 .mu.m)/(number of particles smaller than 1 .mu.m)
increases. The number of particles of the second-order disperse phase
dispersed in the first-order disperse phase is at least two. With the
number being only one, sufficient improvements in physical properties such
as impact resistance cannot be obtained. The ratio of the second-order
disperse phase in the first-order disperse phase is at least 10%,
preferably at least 15%, in terms of a crosssectional area ratio
determined on a transmission electron miscograph taken by utilizing
staining with phosphotungstic acid. If the ratio is less than 10%, the
effects of improving physical properties are insufficient.
The chemical bond between the matrix phase and the first-order disperse
phase or between the first-order disperse phase and the second-order
disperse phase of the multi-phase structure of the present invention is
considered to be a chemical bond primarily formed by the reaction between
the terminal amino group of the polyamide resin and the acid anhydride
group of the ethylene copolymer. It is believed that the chemical bond,
too, makes a contribution to improvements of physical properties of the
multi-phase structure of the present invention.
By constructing the components into a multi-phase structure as illustrated
above, impact resistance as well as flow characteristics, i.e.,
processability, of a polyamide resin can be improved without reducing
thermal distortion resistance or rigidity. Taking into consideration a
general tendency that an improvement in impact resistance leads to
deterioration in thermal distortion resistance and rigidity, achievement
of improvements in impact resistance and also processability without
involving reduction of other physical properties by constructing a
multi-phase structure according to the present invention is an effect that
can never be anticipated from the conventional techniques.
The reason why the multi-phase structure of the present invention exhibits
such superior characteristics is considered as follows. As compared with a
two-phase structure formed by mere melt-kneading of a polyamide resin and
an ethylene copolymer, the surface area of the ethylene copolymer per unit
weight in the multi-phase particle structure increases and, as a result, a
so much increased amount of a chemical bond is formed between the matrix
phase and the first-order disperse phase and between the first-order
disperse phase and the second-order disperse phase, whereby impact energy
is smoothly absorbed and dissipated in, for example, impact test. Further,
since the ethylene copolymer having its melt viscosity increased by
partial crosslinking is made a disperse phase with the polyamide resin
having satisfactory fluidity at high temperatures being made a matrix
phase, it appears that the multi-phase structure exhibits satisfactory
melt fluidity characteristics and processability.
While satisfactory physical properties and processability are assured
irrespective of conditions of production as long as the multi-phase
structure as described above is obtained, preferred processes for
producing the multi-phase structure according to the present invention are
described below.
The multi-phase structure of the present invention can be produced by a
process comprising kneading the constituent components in a molten state.
Manners of kneading are roughly divided into the following two processes.
The first process comprises melt-kneading the polyamide resin (A) and
ethylene copolymer (B) to prepare a composition and then adding the
polyfunctional compound (C) to the composition while the ethylene
copolymer constitutes a matrix phase, followed by melt-kneading to conduct
a partial crosslinking reaction. In this case, the order and timing of
melt-kneading are of great importance. If melt-kneading of the polyamide
resin (A) is preceded by melt-kneading of the ethylene copolymer (B) and
polyfunctional compound (C), or if the components A), (B), and (C) are
melt-kneaded all at once, it seems difficult to obtain the multi-phase
structure of the present invention. This is assumably because the ethylene
copolymer (B) first reacts with the polyfunctional compound (C) to have an
increased viscosity, thereby reducing reactivity with the polyamide resin
(A) and, as a result, chemical bonding force between the matrix phase and
the first-order disperse phase and between the first-order disperse phase
and the second-order disperse phase would be weakened. Since the ethylene
copolymer (B) has a lower melting point than the polyamide resin (A), the
former constitutes a matrix phase in the initial stage of the
melt-kneading of the polyamide resin (A) and ethylene copolymer (B). By
addition of the polyfunctional compound (C) while the ethylene copolymer
(B) constitutes a matrix phase, the melt viscosity of the ethylene
copolymer (B) is increased while inhibiting the polyamide resin (A)
present in a larger proportion from phase transition to a matrix phase and
stopping the polyamide resin (A) in a state of incomplete phase
transition, to thereby form the multi-phase structure according to the
present invention. Therefore, addition of the polyfunctional compound (C)
after complete phase transition of the polyamide resin (A) to a matrix
phase is no more effective to form the multi-phase structure of the
invention.
The second process of melt-kneading is the process as described and claimed
in the present application. The process according to the present invention
comprises a step of melt-kneading the polyamide resin (A-1) and ethylene
copolymer (B) to prepare a composition (I) in which the ethylene copolymer
(B) constitutes a matrix phase; a step of adding the polyfunctional
compound (C) to the composition (I) followed by melt-kneading to cause
partial crosslinking to prepare a composition (II); and a step of adding a
polyamide resin to composition (II) followed by melt-kneading to produce a
multi-phase structure. In the composition (I), the ethylene copolymer
forms a stable matrix phase because its proportion to the polyamide resin
is relatively high. Addition of the polyfunctional compound to such a
stable dispersion results in the production of a multi-phase structure
with excellent reproducibility. In general, it is not easy to produce a
polymer alloy having a multi-phase structure with good reproducibility.
Then, addition of the polyamide resin in the third step accelerates phase
transition of the polyamide resin to a matrix phase, but the phase
transition is considered to be inhibited because of the increased melt
viscosity of the ethylene copolymer which resulted from the addition of
the polyfunctional compound. As a result, the phase transition of the
polyamide resin appears to stop in an incomplete state to thereby provide
the multi-phase structure according to the present invention. The
polyamide resin which is added in the third step may be either the same or
different from the polyamide resin (A-1). It is preferable to choose a
polyamide resin suited for improving physical properties and
processability.
In carrying out partial crosslinking in the second step and addition of the
polyamide resin in the third step, the polyamide resin (A-1) and ethylene
copolymer (B) may be melt-kneaded and pelletized to once obtain the
composition (I) in the form of pellets, and the polyfunctional compound
(C) is then added followed by melt-kneading and pelletization to obtain
the composition (II). Then, a polyamide resin is added thereto, followed
by melt-kneading and pelletization. In a preferred embodiment, however, an
extruder with side feed openings is employed to produce the multi-phase
structure through one stage with good economy. According to this
embodiment, the polyamide resin (A-1) and ethylene copolymer (B) are
melt-kneaded in the front zone of a barrel to prepare the composition (I),
and the polyfunctional compound (C) either in a solid state or in a molten
state is fed from a side feed opening provided in the rear zone to prepare
the composition (II), and the polyamide resin is successively fed from a
different side feed opening in the rear zone, melt-kneaded, and
pelletized. It is also possible to dry blend pellets of the composition
(II) and the polyamide resin, and the resulting compound is directly
molded to obtain a molded article having satisfactory physical properties.
In addition, it is also preferable that the polyfunctional compound (C) is
previously melt-kneaded with a resin inert to the polyfunctional compound
to prepare a master batch which is then added in an adequate amount in the
production of the multi-phase structure.
Prior to kneading, it is preferable to mix each resinous component
uniformly in the form of powder or pellets using a tumbler, a Henschel
mixer, or the like means. If desired, such mixing may be omitted, and each
resinous component may be fed separately to a kneading apparatus in a
fixed quantity.
If desired, the resin composition of this invention may further contain
other components, such as additives, e.g., pigments, dyes, reinforcements,
fillers, heat stabilizers, antioxidants, weathering agents, nucleating
agents, lubricants, antistatic agents, flame retarders, and plasticizers;
or other polymers, e.g., polyethylene, an ethylene-propylene rubber, a
maleic anhydride-grafted modified polyolefin, and a maleic
anhydride-grafted modified ethylene-propylene rubber.
Addition of a reinforcement or filler, e.g., various surface-treated glass
fibers, carbon fibers, talc, calcium carbonate, and magnesium hydroxide,
especially provides a very useful material having high rigidity as well as
high impact strength.
The kneaded resin composition according to the present invention can be
molded by injection molding, extrusion molding or other various molding
techniques.
The present invention is now illustrated in greater detail by way of the
following Examples, but it should be understood that the present invention
is not construed as being limited thereto. In the following description,
all the parts, percents and ratios are given by weight unless otherwise
indicated.
Various physical properties of samples prepared in the Examples were
measured and evaluated according to the following methods.
1) Flexural Modulus:
Measured according to JIS K7203. Thickness of specimens: 3.2 mm.
Measurement Temperature: 23.degree. C.
2) Izod Impact Strength (V-notched):
Measured according to JIS K7110. Thickness of Specimens: 3.2 mm.
Measurement Temperature: 23.degree. C. or -40.degree. C.
3) Thermal Distortion Temperature:
Measured according to JIS K7207. Thickness of Specimens: 3.2 mm. Flexure
Stress: 4.6 kgf/cm.sup.2.
4) Melt Index (MI):
Measured according to JIS K6760 (load: 2,160 g).
5) Particle Structure:
The particle structure of a sample was examined by observing a transmission
electron micrograph of a specimen. The specimen was prepared by slicing an
injection molded sheet with a ultramicrotome and dipping the slice in a
phosphotungstic acid solution at 60.degree. C. for 30 minutes to stain the
polyamide resin phase.
6) Melting Point:
Measured with a differential scanning calorimeter (DSC).
7) Relative Viscosity:
Measured according to a sulfuric acid method of JIS K6810.
8) Terminal Amino Group Concentration:
The terminal amino group of a polyamide resin was determined on an m-cresol
solution of a sample by neutralization titration with p-toluenesulfonic
acid.
9) Terminal Carboxyl Group Concentration:
The terminal carboxyl group of a polyamide resin was determined on a benzyl
alcohol solution of a sample by neutralization titration with sodium
hydroxide.
Polyamide resins, ethylene copolymers, and polyfunctional compounds used in
the following Examples and Comparative Examples are shown below.
1) Polyamide Resin
Polyamide 6:
A1022S (manufactured by Unitika, Ltd.):
MI at 230.degree. C.: 114 g/10 min, relative viscosity: 2.15
dl/g, concentration of terminal amino group: 35 eq./10.sup.6
g, concentration of terminal carboxyl group: 86 eq./10.sup.6
g, concentration ratio of terminal carboxyl group to terminal amino group:
2.5, melting point: 225.degree. C.
1013B (manufactured by Ube Industries, Ltd.):
MI at 230.degree. C.: 38 g/10 min, concentration of terminal
amino group: 39 eq./10.sup.6 g, concentration of terminal
carboxyl group: 75 eq./10.sup.6 g, concentration ratio of terminal carboxyl
group to terminal amino group: 1.9, melting point: 225.degree. C.
A1020BRL (manufactured by Unitika, Ltd.):
MI at 230.degree. C.: 90 g/10 min, relative viscosity: 2.1 dl/g,
concentration of terminal amino group: 84 eq./10.sup.6 g,
concentration of terminal carboxyl group: 84 eq./10.sup.6 g, concentration
ratio of terminal carboxyl group to terminal amino group: 1.0, melting
point: 225.degree. C.
A1030BRL (manufactured by Unitika, Ltd.):
MI at 230.degree. C.: 31 g/10 min, relative viscosity: 2.6 dl/g,
concentration of terminal amino group: 60 eq./10.sup.6 g,
concentration of terminal carboxyl group: 60 eq./10 g, concentration ratio
of terminal carboxyl group to terminal amino group: 1.0, melting point:
225.degree. C.
A1030BRT (manufactured by Unitika, Ltd.):
MI at 230.degree. C.: 7 g/10 min, relative viscosity: 3.4 dl/g,
concentration of terminal amino group: 42 eq./10.sup.6 g,
concentration of terminal carboxyl group: 42 eq./10.sup.6 g, concentration
ratio of terminal carboxyl group to terminal amino group: 1.0, melting
point: 225.degree. C.
Polyamide 6.6:
B (manufactured by Ube Industries, Ltd.):
MI at 280.degree. C.: 150 g/10 min or more, relative viscosity:
2.36 dl/g, concentration of terminal amino group: 47
eq./10.sup.6 g, concentration of terminal carboxyl group: 86 eq./10.sup.6
g, concentration ratio of terminal carboxyl group to terminal amino group:
1.8, melting point: 261.degree. C.
A2020B (manufactured by Unitika, Ltd.):
MI at 280.degree. C.: 49 g/10 min, relative viscosity: 2.63
dl/g, concentration of terminal amino group: 38 eq./10.sup.6
g, concentration of terminal carboxyl group: 102 eq./10.sup.6 g,
concentration ratio of terminal carboxyl group to terminal amino group:
2.68, melting point: 261.degree. C.
A125 (manufactured by Unitika, Ltd.):
MI at 280.degree. C.: 68 g/10 min, relative viscosity: 2.70
dl/g, concentration of terminal amino group: 56 eq./10.sup.6 g,
concentration of terminal carboxyl group: 70 eq./10.sup.6 g, concentration
ratio of terminal carboxyl group to terminal amino group: 1.25, melting
point: 256.degree. C.
2) Ethylene Copolymer (B)
Copolymer-1:
E/EA/MAH=71.9/25.0/3.1; MI (190.degree. C.): 33 g/10 min; Melting Point:
68.degree. C.
Copolymer-2:
E/MA/MAH 70.2/27.8/2.0; MI (190.degree. C.): 15 g/10 min; Melting Point:
67.degree. C.
Abbreviations used above have the following meanings:
E: ethylene
EA: ethyl acrylate
MAH: maleic anhydride
MI: melt index
Ethylene copolymers-1 and 2 can be prepared by the methods described in
JP-A-61-60708 and JP-A-61-60709.
3) Polyfunctional Compound (C)
MB-1:
Master batch prepared by melt-kneading 5 parts of hexamethylenediamine
carbamate and 95 parts of Grilon.RTM. CF 6S (copolymer polyamide resin
produced by EMS Chemie AG) at 150.degree. C. by means of a vented 30
mm.phi. single-screw extruder.
MB-2:
Master batch prepared by melt-kneading 10 parts of hexamethylenediamine
carbamate and 90 parts of Grilon.RTM. CF 6S at 150.degree. C. by means of
a vented 30 mm.phi. single-screw extruder.
Bondfast.RTM.:
Ethylene/glycidyl methacrylate copolymer produced by Sumitomo Chemical Co.,
Ltd.; glycidyl methacrylate unit content: 12%; MI (190.degree. C.): 3 g/10
min.
EXAMPLES 1 AND 2
A vented 30 mm.phi. (L/D=40) twin-screw extruder having two side feed
openings (Fl, F2) was used as a melt-kneading apparatus. Fl and F2 were on
the points trisecting the extruder barrel, and the vent was on the
extruder die side.
A polyamide resin (A-1), an ethylene copolymer (B), a polyfunctional
compound (C), and a polyamide resin each shown in Table 1 below were
melt-kneaded at 260.degree. C. and pelletized using the above-described
extruder in such a manner that the polyamide resin (A-1) and ethylene
copolymer (B) were fed from the main feed opening, the polyfunctional
compound (C) was then fed from F1, and the polyamide resin was
successively fed from F2. The pellets were dried at 80.degree. C. for 12
hours to obtain a resin composition. The melt index of the resulting
composition was as shown in Table 1.
The composition was molded by the use of a 10-ounce injection molding
machine "Model IS-150-V" (manufactured by Toshiba Corporation) at a resin
temperature of 260.degree. C. and at a mold temperature of 70.degree. C.
to prepare test specimens for measurement of physical properties.
The flexural modulus, Izod impact strength (notched), and thermal
distortion temperature of the specimens are shown in Table 1. Transmission
electron microscopic observation of a slice cut from the cross section of
the molded specimen revealed a multi-phase structure of particles.
The transmission electron micrograph of the multi-phase structure obtained
in Example 1 is shown in FIG. 1. In FIG. 1, the black part is a stained
polyamide resin phase, and the white part is an ethylene copolymer phase.
It can be seen that the polyamide resin constitutes a matrix phase and
also constitutes a second-order disperse phase in a first-order disperse
phase comprising the ethylene copolymer. The particle size of the
first-order disperse phase is from 0.2 to 5 .mu.m. The polyamide resin
constituting the second-order disperse phase is more finely dispersed in
the first-order disperse phase.
COMPARATIVE EXAMPLE 1
A polyamide resin composition was produced in the same manner as in Example
1, except for replacing MB-1 with Grilon.RTM. CF 6S. The results obtained
are shown in Table 1 below. An electron micrograph of the resulting molded
product is shown in FIG. 2.
As is shown in FIG. 2, the molded product obtained from the composition of
Comparative Example 1 revealed a fine dispersion having no multi-phase
structure. Further, the composition has poor melt fluidity and fairly
inferior Izod impact strength.
COMPARATIVE EXAMPLE 2
A polyamide resin composition was produced in the same manner as in Example
1, except that polyamide resin (A-1), ethylene copolymer (B), and
polyfunctional compound (C) each shown in Table 1 below were fed all at
once to the same twin-screw extruder as used in Example 1 from the main
feed opening, melt-kneaded at 260.degree. C., pelletized, and dried at
80.degree. C. for 12 hours. The results obtained are shown in Table 1 and
FIG. 3.
Observation on the phase separation structure (FIG. 3) revealed a
dispersion of giant particles having no multi-phase structure. Further,
the composition was very poor in Izod impact strength.
COMPARATIVE EXAMPLES 3 AND 4
A polyamide resin composition was produced in the same manner as in Example
1, except for using a polyamide resin having a concentration ratio of
terminal carboxyl group to terminal amino group of less than 1.5 as shown
in Table 1 below. The results obtained are shown in Table 1. A
transmission electron micrograph of the molded product obtained in
Comparative Example 3 is shown in FIG. 4.
Electron microscopic observation on the composition of Comparative Example
3 revealed a fine dispersion having substantially no multi-phase
structure. Further, the compositions of Comparative Examples 3 and 4 had
poor melt fluidity and inferior Izod impact strength.
EXAMPLE 3
A polyamide resin composition was produced in the same manner as in Example
1, except for carrying out melt-kneading at 280.degree. C. and carrying
out injection molding at 290.degree. C. The results obtained are shown in
Table 1 and FIG. 5.
Electron microscopic observation on the phase separation structure (FIG. 5)
revealed a multi-phase structure similar to that of Example 1.
COMPARATIVE EXAMPLE 5
A polyamide resin composition was produced in the same manner as in Example
3, except for using a polyamide resin having a concentration ratio of
terminal carboxyl group to terminal amino group of less than 1.5 as shown
in Table 1. The results obtained are shown in Table 1 and FIG. 6.
Electron microscopic observation on the phase separation structure (FIG. 6)
revealed a fine dispersion having substantially no multi-phase structure.
Further, the composition had poor melt fluidity and inferior Izod impact
strength.
TABLE 1
__________________________________________________________________________
Heat
Distor-
Flex- sion
Polyamide Ethylene ural Tempera-
Resin (A-1) Co- Poly- Mod-
Izod Impact
ture
Kind and
COOH/
polymer
functional
Polyamide
MI ulus
Strength (4.6
Multi-
Example
Amount
NH B Compound (C)
Resin (g/10
(kg/
23.degree. C.
-40.degree. C.
cm.sup.2)
Phase
No. (part)
Ratio*.sup.2
(part)
(part) (part)
min) cm.sup.2)
(kg .multidot. cm/cm)
(.degree.C.)
Structure
__________________________________________________________________________
Example
A1022S
86/35 =
Copoly-
MB-1 A1030BRT
5 18700
NB**
15 167 observed
1 20 2.5 mer-1
4.4 55.6 (230.degree. C.) (FIG. 1)
20
Com- A1022S
86/35 =
Copoly-
Grilon .RTM. CF6S
A1030BRT
2 18500
28 6 160 not
parative
20 2.5 mer-1
4.4 55.6 (230.degree. C.) observed
Example 20 (FIG. 2)
Com- A1022S
-- Copoly-
MB-1 -- 2 17500
15 4 170 not
parative
20 mer-1
4.4 (230.degree. C.) observed
Example
A1030BRT 20 (FIG. 3)
2 55.6
Com- A1020BRL
84/84 =
Copoly-
MB-1 A1030BRT
0.6 18600
NB 8 168 substan-
parative
20 1.0 mer-1
4.4 55.6 (230.degree. C.) tially not
Example 20 observed
3 (FIG. 4)
Example
1013B 75/39 =
Copoly-
Bondfast .RTM. E
A1030BRL
18 19100
NB 12 174 observed
2 13.3 1.9 mer-1
3.3 66.7 (230.degree. C.)
16.7
Com- A1030BRL
60/60 =
Copoly-
Bondfast .RTM. E
A1030BRL
10 19000
NB 7 175 substan-
parative
13.3 1.0 mer-1
First E 66.7 (230.degree. C.) tially not
Example 16.7 3.3 observed
4
Example
2015B 86/47 =
Copoly-
MB-2 2020B 11 20200
NB 15 205 observed
3 18 1.8 mer-2
2 60 (280.degree. C.) (FIG. 5)
20
Com- A125 70/56 =
Copoly-
MB-2 2020B 6 20100
NB 8 204 substan-
parative
18 1.25 mer-2
2 60 (280.degree. C.) tially not
Example 20 observed
5 (FIG.
__________________________________________________________________________
6)
Note:
*Concentration ratio of terminal carboxyl group (eq./10.sup.6 g) to
terminal amino group (eq./10.sup.6 g)
**"NB" means that the sample had an Izod impact strength (notched) of mor
than 50 kg .multidot. cm/cm and did not break.
As described above, the multi-phase structure in accordance with the
present invention is obtained by specifying a compounding ratio and a
manner of melt-kneading of the constituent components, i.e., a polyamide
resin, an ethylene copolymer, and a partial crosslinking agent
(polyfunctional compound). It has a novel phase separation structure in
which a part of the polyamide resin constitutes a matrix phase, the
partially crosslinked ethylene copolymer constitutes a first-order
disperse phase, and the rest of the polyamide resin is dispersed in the
first-order disperse phase to constitute a second-order disperse phase.
The multi-phase structure having such a phase separation structure provides
a resin molding material having well-balanced physical properties, such as
impact resistance, rigidity, and thermal resistance, while exhibiting
satisfactory moldability (fluidity).
In particular, by limiting a concentration ratio of terminal carboxyl group
to terminal amino group of the polyamide resin to be employed,
improvements are added to the conventional techniques thereby obtaining
satisfactory physical properties and moldability in a stable manner.
While the invention has been described in detail and with reference to
specific embodiments thereof, it will be apparent to one skilled in the
art that various changes and modifications can be made therein without
departing from the spirit and scope thereof.
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